Covers for vehicles such as a load-carrying truck body are known in the art. See, for example, U.S. Pat. No. 4,673,208, issued Jun. 16, 1987 to M. Tsukarnoto for "Power-Operated Extendable and Retractable Cover for Truck Beds." This patent discloses an elongated roller which is movable back and forth transversely across the bed of a truck from one side to the other. The roller carries a rolled cover sheet, which is unrolled and re-rolled during the back and forth movement to cover a load in the truck bed. Levers pivotally mounted at opposite ends of the truck carry the roller and are moved by hydraulic power cylinders controlled from inside the cab of the truck. The roller is driven by a chain-and-sprocket arrangement and an elastic draw cord and backup plate arrangement at opposite ends of the truck bed secures and seals the cover sheet at the opposite ends of the bed.
A cover for a slide-out or expandable section of a trailer or like vehicle is shown in U.S. Pat. No. 4,955,661, issued Sep. 11, 1990, to R. Mattice for "Environmentally Protected Expandable Trailer." This patent discloses an automatically retracting cover over the expandable section to prevent accumulation of snow, water, dirt or the like on top of the expandable section.
A top cover and awning combination for an expandable section of a recreational vehicle is shown in U.S. Pat. No. 5,171,056, issued Dec. 15, 1992, to T. Faludy, et al. for "Retractable Awning for Slide-Out Unit on Mobile Home, Recreational Vehicle or the Like." The retractable awning and top cover is secured along an inner edge to the side of the mobile home. The opposite edge of the awning is secured to a torsionally biased roll bar rotatably mounted on the outer ends of support arms, which are pivotally mounted to the outer face of the slide-out unit. The awning sheet overlies the top of the slide-out unit when it is extended and further provides an awning for a window in the slide-out unit.
A need exists for an improved top cover, and improved mechanism for deploying and retracting the top cover, for shading the roof of a recreational vehicle or like structure.